1. Field of the Invention
The present invention relates to a blood analyzer and a blood analysis method for optically measuring a blood specimen and classifying hemocytes contained in the blood specimen, and a computer program product for enabling a computer to analyze blood.
2. Description of the Related Art
Five types of leukocyte consisting of lymphocytes, monocytes, basophils, eosinophils, and neutrophils are present in normal peripheral blood, and many blood cell counting apparatuses have the function of classifying leukocytes contained in a blood specimen into the five types. On the other hand, cells that are not present in normal peripheral blood appear in peripheral blood affected with diseases such as viral infectious diseases and hematopoietic system diseases. Abnormal leukocytes that appear in peripheral blood include abnormal mononuclear leukocytes, which can be largely categorized into reactive abnormal mononuclear leukocytes and neoplastic abnormal mononuclear leukocytes. Reactive abnormal mononuclear leukocytes include “atypical lymphocytes”, which can be observed for viral infection, drug allergy, and the like. Neoplastic abnormal mononuclear leukocytes can be further categorized into neoplastic mature abnormal mononuclear leukocytes and neoplastic immature abnormal mononuclear leukocytes. Neoplastic mature mononuclear leukocytes include “abnormal lymphocytes”, which can be observed for e.g. chronic lymphocytic leukemia (CLL). Neoplastic immature mononuclear leukocytes include “blasts”, which can be observed for e.g. acute leukemia. Distinguishably detecting atypical lymphocytes, abnormal lymphocytes, and blasts in peripheral blood is very useful in screening or diagnosis of diseases as described above.
Japanese Laid-Open Patent Publication No. 2006-91024 discloses detecting atypical lymphocytes and myeloblasts distinguishably from normal leukocytes using reagents for classifying leukocytes into four or five categories (see FIGS. 12 and 14). U.S. Patent Publication No. 2009/0023129 discloses detecting a cell group consisting of abnormal lymphocytes and blasts distinguishably from normal leukocytes using reagents for classifying leukocytes into five categories (see FIG. 2). The techniques disclosed in these documents are similar in that they use a hemolyzing agent containing a cationic surfactant and a nonionic surfactant, and a stain solution containing a fluorescent dye for staining nucleic acid as the reagents for classifying leukocytes. However, atypical lymphocytes, abnormal lymphocytes, and blasts appear in substantially the same area for fluorescence intensity and scattered light intensity in Japanese Laid-Open Patent Publication No. 2006-91024 and U.S. Patent Publication No. 2009/0023129, and therefore cannot be distinguished from one another.
U.S. Patent Publication No. 2007/231913 discloses detecting myeloblasts distinguishably from mature leukocytes and immature granulocytes using predetermined reagents (see FIGS. 1, 2, and 5). This document discloses, as the above-described reagents, a hemolyzing agent containing a nonionic surfactant and a solubilizing agent, and a fluorescent dye for staining nucleic acid. U.S. Patent Publication No. 2010/248247 discloses distinguishably detecting lymphoblasts, myeloblasts, mature leukocytes, and immature granulocytes using predetermined reagents (see FIGS. 13A and 13B). This document discloses, as the above-described reagents, a hemolyzing agent containing a nonionic surfactant and a solubilizing agent, and a fluorescent dye for staining nucleic acid. However, neither U.S. Patent Publication No. 2007/231913 nor U.S. Patent Publication No. 2010/248247 discloses detecting atypical lymphocytes distinguishably from abnormal lymphocytes.